At the present time, swimming pools generally require a complex array of plumbing and electrical components to provide filtration of the pool water. For example, a typical pool consists of a skimmer, main drain, suction piping and valves to connect suction to a pump. The pump discharge is connected to a pressure vessel type filter. The filter is then connected back to the pool through discharge piping. A typical plumbing system also has 30 to 40 feet of suction piping with numerous elbows and fittings. The discharge piping may consist of 50 to 70 feet of discharge piping to return the filtered water to the pool. The usual practice is to locate the filter and pump at a remote location away from the pool wall and above ground level. The complex array of plumbing is typically done at the job site with hand tools. Many times the plumbing is done with little knowledge of hydraulics and consequently many systems perform poorly and cause pool owners numerous problems. The plumbing system of piping is typically buried in trenches which must be dug from the pool walls to the filter pump site. In addition to the work required to install this complicated system of piping, elbows, valves, fittings, etc. one normally has to overcome relatively high total dynamic head. The high dynamic head causes a substantial loss of "flow" which is needed to filter the pool water properly. This causes the installer to use a much larger pump and motor which consumes considerable power. It is thus apparent that a need exists for a unit which is capable of being prefabricated and brought to the swimming pool site and installed in place, and which may be a part of the swimming pool wall, without the extra expense and cumbersome task of using relatively extensive lengths of piping and building an array of discharge and return trenches and without the need to install numerous other relatively labor intensive plumbing, electrical and mechanical elements.